Ingredients for the specification of mixed-criticality real-time systems

Models for real-time computing are available with different timing requirements. With the ongoing trend towards integration of services of different degrees of timing strictness on one single platform, there is a need to specify computing models for such scenarios. In this paper we study the requirements to specify mixed criticality real-time systems (MCRTS). Mixed criticality systems have been studied intensively over the last years. Existing formulations of the scheduling problem for mixed criticality systems do not consider the different timing strictness requirements of the tasks. In this paper we argue that mixed criticality properties as well as real-time properties have to be considered together in order to provide the maximal utility of a system. Based on that argument we present a list of ingredients required for the specification of MCRTS. We outline conceptually, how a system can take advantage of having MCRTS specifications available. We present some examples to show the usefulness of specifying MCRTS properties for real-life systems.Final Accepted Versio

Exploiting tightly-coupled cores

This is the published manuscript. It was first published by Springer in the Journal of Signal Processing Systems here: http://link.springer.com/article/10.1007%2Fs11265-014-0944-6.The individual processors of a chip-multiprocessor traditionally have rigid boundaries. Inter-core communication is only possible via memory and control over a core’s resources is localised. Specialisation necessary to meet today’s challenging energy targets is typically provided through the provision of a range of processor types and accelerators. An alternative approach is to permit specialisation by tailoring the way a large number of homogeneous cores are used. The approach here is to relax processor boundaries, create a richer mix of intercore communication mechanisms and provide finer-grain control over, and access to, the resources of each core. We evaluate one such design, called Loki, that aims to support specialisation in software on a homogeneous many-core architecture. We focus on the design of a single 8-core tile, conceived as the building block for a larger many-core system. We explore the tile’s ability to support a range of parallelisation opportunities and detail the control and communication mechanisms needed to exploit each core’s resources in a flexible manner. Performance and a detailed breakdown of energy usage is provided for a range of benchmarks and configurations.This work was supported by EPSRC grant EP/G033110/1

Enhancing the Automotive E/E Architecture Utilising Container-Based Electronic Control Units

Over the past 40 years, with the advent of computing technology and embedded systems, such as Electronic Control Units (ECUs), cars have moved from solely mechanical control to predominantly digital control. Whilst improvements have been realised in terms of passenger safety and vehicle efficiency, there are several issues currently facing the automotive industry as a result of the rising number of ECUs. These include greater demands placed on power, increased vehicle weight, complexities of hardware and software, dependency on software, software life expectancy, ad-hoc methods concerning automotive software updates, and rising costs for the vehicle manufacturer and consumer. As the modern-day motor car enters the autonomous age, these issues are predicted to increase because there will be an even greater reliance on computing hardware and software technology to support these new driving functions. To address the issues highlighted above, a number of solutions that aid hardware consolidation and promote software reusability have been proposed. However, these depend on bespoke embedded hardware and there remains a lack of clearly defined mechanisms through which to update ECU software. This research moves away from these current practices and identifies many similarities between the datacentre and the automotive Electronic and Electrical (E/E) architecture, demonstrating that virtualisation technologies, which have provided many benefits to the datacentre, can be replicated within an automotive context. Specifically, the research presents a comprehensive study of the Central Processor Unit (CPU) and memory resources required and consumed to support a container-based ECU automotive function. The research reveals that lightweight container virtualisation offers many advantages. A container-based ECU can promote consolidation and enhance the automotive E/E architecture through power, weight and cost savings, as well as enabling a robust mechanism to facilitate future software updates throughout the lifetime of a vehicle. Furthermore, this research demonstrates there are opportunities to adopt this new research methodology within both the automotive industry and industries that utilise embedded systems, more broadly

Power Consumption Analysis, Measurement, Management, and Issues:A State-of-the-Art Review of Smartphone Battery and Energy Usage

The advancement and popularity of smartphones have made it an essential and all-purpose device. But lack of advancement in battery technology has held back its optimum potential. Therefore, considering its scarcity, optimal use and efficient management of energy are crucial in a smartphone. For that, a fair understanding of a smartphone's energy consumption factors is necessary for both users and device manufacturers, along with other stakeholders in the smartphone ecosystem. It is important to assess how much of the device's energy is consumed by which components and under what circumstances. This paper provides a generalized, but detailed analysis of the power consumption causes (internal and external) of a smartphone and also offers suggestive measures to minimize the consumption for each factor. The main contribution of this paper is four comprehensive literature reviews on: 1) smartphone's power consumption assessment and estimation (including power consumption analysis and modelling); 2) power consumption management for smartphones (including energy-saving methods and techniques); 3) state-of-the-art of the research and commercial developments of smartphone batteries (including alternative power sources); and 4) mitigating the hazardous issues of smartphones' batteries (with a details explanation of the issues). The research works are further subcategorized based on different research and solution approaches. A good number of recent empirical research works are considered for this comprehensive review, and each of them is succinctly analysed and discussed

2022 roadmap on neuromorphic computing and engineering

Modern computation based on von Neumann architecture is now a mature cutting-edge science. In the von Neumann architecture, processing and memory units are implemented as separate blocks interchanging data intensively and continuously. This data transfer is responsible for a large part of the power consumption. The next generation computer technology is expected to solve problems at the exascale with 10$^{18}$ calculations each second. Even though these future computers will be incredibly powerful, if they are based on von Neumann type architectures, they will consume between 20 and 30 megawatts of power and will not have intrinsic physically built-in capabilities to learn or deal with complex data as our brain does. These needs can be addressed by neuromorphic computing systems which are inspired by the biological concepts of the human brain. This new generation of computers has the potential to be used for the storage and processing of large amounts of digital information with much lower power consumption than conventional processors. Among their potential future applications, an important niche is moving the control from data centers to edge devices. The aim of this roadmap is to present a snapshot of the present state of neuromorphic technology and provide an opinion on the challenges and opportunities that the future holds in the major areas of neuromorphic technology, namely materials, devices, neuromorphic circuits, neuromorphic algorithms, applications, and ethics. The roadmap is a collection of perspectives where leading researchers in the neuromorphic community provide their own view about the current state and the future challenges for each research area. We hope that this roadmap will be a useful resource by providing a concise yet comprehensive introduction to readers outside this field, for those who are just entering the field, as well as providing future perspectives for those who are well established in the neuromorphic computing community

Fibre-reinforced additive manufacturing: from design guidelines to advanced lattice structures

In pursuit of achieving ultimate lightweight designs with additive manufacturing (AM), engineers across industries are increasingly gravitating towards composites and architected cellular solids; more precisely, fibre-reinforced polymers and functionally graded lattices (FGLs). Control over material anisotropy and the cell topology in design for AM (DfAM) offer immense scope for customising a part’s properties and for the efficient use of material. This research expands the knowledge on the design with fibre-reinforced AM (FRAM) and the elastic-plastic performance of FGLs. Novel toolpath strategies, design guidelines and assessment criteria for FRAM were developed. For this purpose, an open-source solution was proposed, successfully overcoming the limitations of commercial printers. The effect of infill patterns on structural performance, economy, and manufacturability was examined. It was demonstrated how print paths informed by stress trajectories and key geometric features can outperform conventional patterns, laying the groundwork for more sophisticated process planning. A compilation of the first comprehensive database on fibre-reinforced FGLs provided insights into the effect of grading on the elastic performance and energy absorption capability, subject to strut-and surface-based lattices, build direction and fibre volume fraction. It was elucidated how grading the unit cell density within a lattice offers the possibility of tailoring the stiffness and achieving higher energy absorption than ungraded lattices. Vice versa, grading the unit cell size of lattices yielded no effect on the performance and is thus exclusively governed by the density. These findings help exploit the lightweight potential of FGLs through better informed DfAM. A new and efficient methodology for predicting the elastic-plastic characteristics of FGLs under large strain deformation, assuming homogenised material properties, was presented. A phenomenological constitutive model that was calibrated based upon interpolated material data of uniform density lattices facilitated a computationally inexpensive simulation approach and thus helps streamline the design workflow with architected lattices.Open Acces

Optimum design of composite structures using lamination parameters

The optimised design of composite structures has attracted great interest from researchers, in the pursuit of developing more effective and efficient optimisation methods. In this thesis, two-stage layup optimisation methods based on the use of lamination parameters are developed for both single laminates and large-scale composite laminates with ply drop-offs

Ion-exchange in Glasses and Crystals: from Theory to Applications

Since its first observation in 1850, ion-exchange (IEx) has become a fundamental process in many applications involving water treatment, catalysis, chromatography, and the food and pharmaceutical industries. Starting from the early 1900s, another relevant application of IEx has been in the glass industry, with the surface tempering of glass produced by a K+–Na+ ion exchange. Nowadays, photonics has greatly exploited IEx technology: graded-index microlenses, graded-index fibers and integrated optical waveguides and devices are examples of achievements made possible by the IEx process. Moreover, ion-exchange is possible in ferroelectric crystals, too, and has been fundamental for the development of many linear and nonlinear integrated optical devices in lithium niobate and tantalate.This volume collects articles published in the corresponding Special Issue of the Applied Sciences journal. Four review articles, written by internationally renowned experts in this field, provide complementary overviews of the history, fundamental aspects, designs and fabrications of devices, and technological achievements. Three articles describe original research in the fields of diffraction grating, photo-thermo-refractive glasses, and Yb-doped lithium niobate. This volume constitutes a valuable and updated reference for all students and researchers wishing to improve their knowledge and/or make use of ion-exchange technology and its applications